First records of Posidonia oceanica flowering at its westernmost distributional limit (Málaga, Alboran Sea)

Abstract

Flowering events of Posidonia oceanica (over two consecutive years) are reported for the first time in meadows located close to its westernmost distribution limit (Málaga, southern Spain). Shoots with inflorescences were found in fragmented meadows (patches between 1–130 m²) at a mean depth of 2.5 m. In March 2009, flowering was only observed in Calaburras (0–28 inflorescences m^-2) and not in Calahonda. In November 2009, massive flowering events were observed in both Calaburras (4–144 inflorescences m^-2) and Calahonda (8–184 inflorescences m^-2). On this occasion, developing fruits were also observed. From 2003 to 2009, mean annual water temperatures increased in this area, with maximum values in late summer and autumn of 2007 and 2008, and these warm waters may have induced the massive flowering events. Flowering in these P. oceanica meadows located close to the Atlantic Ocean may imply favourable environmental conditions and a good health status, which should be considered in improving conservational strategies for these meadows.